Reference values for the concentrations of As,Cd, Co,Cr, Cu,Fe, I,Hg, Mn,Mo, Ni,Pb, Se,and Zn in selected human tissues and body fluids

This report attempts to formulate reference ranges of elemental concentrations for 15 trace elements in selected human tissues and body fluids. A set of samples consisting of whole blood, blood serum, urine, milk, liver, and hair were chosen and considered for 15 elements of biological significance: As, Cd, Co, Cr, Cu, F, Fe, I, Hg, Mn, Mo, Ni, Pb, Se, and Zn. The results represent wholly or partially data received from 40 countries of the global regions of Africa, Asia, Europe, North, South, and Central America, Australia, and New Zealand. This survey, even if qualitative, has been useful in demonstrating certain trends of trace-element scenarios around the world. It is of course recognized that both diet and environment exert a strong influence on the distribution pattern of several elements, such as As, Cd, Mn, Pb, Se, and Zn. A limited comparison of the available information on soil status of different countries reflected some interesting associations for elements, such as Mn and Zn. Importantly, this study revealed that only a few countries were in a position to identify a reasonable amount of data on samples requested for this project. Regretably, for a number of countries, any dependable data for even such essential elements as Cu, Fe, and Zn were not available. In view of the nutritional importance of many elements, the time is ripe for concerted efforts by intergovernmental agencies to initiate investigations or commission task forces/projects to generate reliable reference data for selected global regions, which sadly lack data of any kind at present.     

硫化砷对人结肠癌细胞株HCT116生长及迁移能力的影响

目的:研究硫化砷对人结肠癌细胞株HCT116迁移能力的影响及其作用机制.方法:以HCT116细胞为研究对象,通过MTT法观察硫化砷对肿瘤细胞活性及增殖能力的影响,通过划痕实验观察硫化砷处理后细胞的迁移能力.Western B1ot、Real-time PCR检测硫化砷处理前后细胞内E-钙粘素、P53、Notch1蛋白的表达及相应mRNA水平的变化.结果:硫化砷对HCT116细胞有抑制增殖的作用,此作用随着剂量的增加而增强.选取无毒剂量的硫化砷(1 μM)处理HCT116细胞24h后,细胞的迁移能力降低了52.00％±7.55％.Western Blot及Real-time PCR结果显示,硫化砷处理后,HCT116细胞内的E-钙粘素蛋白水平及mRNA水平均明显升高,P53蛋白水平增高,但对Notch1蛋白及mRNA水平无明显影响.结论:一定剂量范围的硫化砷能抑制HCT116细胞增殖,并能降低其迁移能力.硫化砷降低HCT116细胞的迁移能力,其机制可能是通过上调P53蛋白的水平,从而增高E-钙粘素的表达实现的.     

Cu、As对作物种子萌发和幼苗生长影响的研究

通过水培实验研究了Cu、As污染对作物种子萌发、幼苗生长及部分酶活性的影响。结果表明,Cu,As污染明显抑制黄豆种子萌发、幼苗生长,对作物种子萌发时的呼吸强度、酶活性有显著的抑制作用,且随着Cu、As浓度的增加,抑制作用增强,呈负相关;而POD活性则随污染物浓度的增加而增加,呈正相关。     

双载体转重链Tyr664Cys和轻链Thr1286Cys突变体BDD-FVⅢ基因

摘要用双载体转运凝血VⅢ因子基因在甲型血友病基因治疗研究中可克服AAV毒载体容量限制,但存在重链分泌低效和链不均衡性问题。为探索重、轻链间二硫键形成对重链分泌的促进作用,该丈用双载体转B结构域大部缺失型FVⅢ（BDD-FVⅢ）的重链和轻链基因,将重链的Tyr664和轻链Thr1826突变为Cys,研究了HEK293细胞共转基因后的基因表达、分泌至培养上清的重链量和凝血生物活性。用Western blot检测细胞裂解液结果显示,非还原条件下有明显的二硫键交联的重、轻链蛋白;链特异性ELISA定量检测细胞分泌的重链为（125＋29）ng／mL,明显高于共转野生型重链和轻链基因细胞的（75＋23）ng／mL;Coatest法显示细胞分泌的凝血活性为（0．784±0．29）U／mL．也明显高于共转野生型重链和轻链基因细胞（0．34＋0．12）U／mL。结果表明,重、轻链间的二硫键形成可提高双载体转FVⅢ基因的功效,为进一步在动物体内转基因提供了实验依据。     

重组黄杆菌肝素酶Ⅲ的纯化、表征及培养条件对酶生产的影响

肝素酶Ⅲ是一种特异性地裂解乙酰肝素的酶,在大肠杆菌中表达时容易形成包涵体.为实现肝素酶Ⅲ的可溶性表达,利用谷胱甘肽-S-转移酶(GST)与肝素酶Ⅲ融合性能,通过构建相应的表达质粒pGEX-heparinaseⅢ,在大肠杆菌中实现了肝素酶Ⅲ的可溶性表达.粗酶通过一步亲和纯化其纯度可达95%以上.通过对LB培养基摇瓶培养Escherichia coli BL21的诱导时机,诱导剂用量、诱导时间等培养条件的优化,确定了该可溶性肝素酶Ⅲ融合蛋白的最适生产条件.通过对纯酶的最适反应温度、pH、Ca~(2+)浓度等一系列性质研究,确定了该酶的最适反应条件.     

FLRT家族研究进展

FLRT家族是通过基因筛检的方法在人类巢蛋白-1的cDNA中发现的一种跨膜蛋白。FLRT家族对于哺乳动物的胚胎发育尤其是组织的形态发生都有着至关重要的作用。研究发现,FLRT家族包含三个重要的结构,分别为富含亮氨酸的重复片段、Ⅲ型纤维连接蛋白区域以及胞质尾区,且不同的结构有着不同的功能。同时,FLRT家族的成员分布于人体各个组织,在各个组织中行使不同的功能,如同型细胞分选与粘附、对成纤维细胞生长因子信号的诱导、颌面部发育、软骨形成、神经系统以及心脏的发育等等。下文就FLRT家族的研究进展作一综述。     

Solubility relationships of arsenic in calcareous soils and its uptake by corn

Summary The concentrations of total, water-extractable and DTPA extractable As were determined in 19 calcareous soils. The activity of HAsO ₄ ^2– was calculated in the experimental soils and superimposed on the thermodynamic solubility isotherms of As minerals. It was observed that all the soils were undersaturated with respect to Ca₃(AsO₄)₂ and Mn₃(AsO₄)₂ (the most insoluble As minerals in the calcareous soils). The activity of Ca²⁺ in these soils was found to be in equilibrium with CaCO₃.Corn was grown in the experimental soils for 25 days. The corn plants were harvested, dried at 60°C, ground and analyzed for the concentrations of As. The concentrations of As in the plants were significantly correlated (P<0.05) to the water extractable As but not to the total and DTPA extractable concentrations of As in the soils. Sodium bicarbonate extractable P was significantly correlated (P<0.05) to both As in the corn and the water soluble As in the soils.     

Molecular characterization of calreticulin from Anopheles stephensi midgut cells and functional assay of the recombinant calreticulin with Plasmodium berghei ookinetes

Transmission blocking vaccines (TBVs) that target the antigens on the midgut epithelium of Anopheles mosquitoes are among the promising tools for the elimination of the malaria parasite. Characterization and analysis of effective antigens is the first step to design TBVs. Calreticulin (CRT), a lectin-like protein, from Anopheles albimanus midgut, has shown antigenic features, suggesting a promising and novel TBV target. CRT is a highly conserved protein with similar features in vertebrates and invertebrates including anopheline. We cloned the full-length crt gene from malaria vector, Anopheles stephensi (AsCrt) and explored the interaction of recombinant AsCrt protein, expressed in a prokaryotic system (pGEX-6p-1), with surface proteins of Plasmodium berghei ookinetes by immunofluorescence assay. The cellular localization of AsCrt was determined using the baculovirus expression system. Sequence analysis of the whole cDNA of AsCrt revealed that AsCrt contains an ORF of 1221 bp. The amino acid sequence of AsCrt protein obtained in this study showed 64% homology with similar protein in human. The AsCrt shares the most common features of CRTs from other species. This gene encodes a 406 amino-acid protein with a molecular mass of 46 kDa, which contains a predicted 16 amino-acid signal peptides, conserved cysteine residues, a proline-rich region, and highly acidic C-terminal domain with endoplasmic reticulum retrieval sequence HDEL. The production of GST-AsCrt recombinant protein was confirmed by Western blot analysis using an antibody against the GST protein. The FITC-labeled GST-AsCrt exhibited a significant interaction with P. berghei ookinete surface proteins. Purified recombinant GST-AsCrt, labeled with FITC, displayed specific binding to the surface of P. berghei ookinetes in comparison with control. Moreover, the expression of AsCrt in baculovirus expression system indicated that AsCrt was localized on the surface of Sf9 cells. Our results suggest that AsCrt could be utilized as a potential target for future studies in TBV area for malaria control.